Most pivot-rotating objects generally apply a hinge device mounted on a fixed object, wherein the object rotates to perform opening and closing operations, for example: door panels, windows, cabinet doors, etc. Referring to FIG. 1 of a well-known recovery torque hinge device 10, said device includes a first wing plate 11, a second wing plate 12, a washer 13, a pivot 14, two set screws 15, a torque spring 16, an adjusting sleeve 17 and an adjusting pin 18; the first and second wing plates 11, 12 are respectively employed on the door panel and frame (not shown), and the sides of said wing plates include counterpart pin joint sleeve members 111, 121. The sleeve members 111, 121 are interactively superimposed, wherein a washer 13 is interposed between the sleeve members for pivotal rotation. The pivot 14 is inserted inside the pin joint sleeve members 111, 121, whereby the first and second wing plate 11, 12 match to form a pin joint. The two set screws 15 are threadedly employed at on the outside peripheral surface of the pin joint sleeve member 111 of the first wing plate 11, and thereby pivot 14 is tightly screwed and fixed, the pivot 14 having a bearing rod 141 that extends from the bottom of pivot 14. The adjusting sleeve 17 can rotatably sleeve inside the pin joint sleeve member 121 of the second wing plate 12; a dent area at the center includes a bearing hole 171 to enable the bearing rod 141 to sleeve inside, and a torque spring 16 is set on the bearing rod 141, wherein the top side is mounted and fixed on the pivot 14 with the bottom side mounted and fixed on the adjusting sleeve 17 so that torque spring 16 can operate on the first and second wing plates 11, 12. An expected amount of torque force is created by the hinge device 10 to automatically close the door. Moreover a slide slot 122 is located in the circumferential direction at the bottom of the pin joint sleeve member 121 of the second wing plate 12, and the outer periphery of the adjusting sleeve 17 includes a number of insert holes 172 at the dent locations of the corresponding slide slot 122. The adjusting pin 18 can be inserted into one of the insert holes 172 at the desired position through the slide slot 122. After the adjusting pin 18 slides along with rotation of the adjusting sleeve 17 to abut against the inner wall of the slide slot 122, the torque spring 16 begins to twist and store energy. As a result, the user can insert the adjusting pin 18 into different insert holes 172 to adjust the torque spring 16 to produce different values of torque force.
The previously described hinge device 10 features a recovering torque effect which still, however, has disadvantages. The well-known hinge device 10 employs an adjusting pin 18 to first block the inner wall of the slide slot 122 before the adjusting sleeve 17 begins to twist the torque spring 16 to produce torque. However, the slide slot 122 can be opened with only just a small distance which results in limited adjusting of torque size. Moreover, the adjusting of the hinge device 10 employs the inserting of the adjusting pin 18 into different positions of the insert holes 172. This type of inset adjustment operation consumes much time and shows to be inconvenient.